Determine how many solutions exist for the system of equations. ${-4x+y = -6}$ ${4x-y = 3}$
Solution: Convert both equations to slope-intercept form: ${-4x+y = -6}$ $-4x{+4x} + y = -6{+4x}$ $y = -6+4x$ ${y = 4x-6}$ ${4x-y = 3}$ $4x{-4x} - y = 3{-4x}$ $-y = 3-4x$ $y = -3+4x$ ${y = 4x-3}$ Just by looking at both equations in slope-intercept form, what can you determine? ${y = 4x-6}$ ${y = 4x-3}$ Both equations have the same slope with different y-intercepts. This means the equations are parallel. ${1}$ ${2}$ ${3}$ ${4}$ ${5}$ ${6}$ ${7}$ ${8}$ ${9}$ ${\llap{-}2}$ ${\llap{-}3}$ ${\llap{-}4}$ ${\llap{-}5}$ ${\llap{-}6}$ ${\llap{-}7}$ ${\llap{-}8}$ ${\llap{-}9}$ ${1}$ ${2}$ ${3}$ ${4}$ ${5}$ ${6}$ ${7}$ ${8}$ ${9}$ ${\llap{-}2}$ ${\llap{-}3}$ ${\llap{-}4}$ ${\llap{-}5}$ ${\llap{-}6}$ ${\llap{-}7}$ ${\llap{-}8}$ ${\llap{-}9}$ Parallel lines never intersect, thus there are NO SOLUTIONS.